Cooper.] ^O" [May 16, 



blance in everything but small size of II. yabbi to this species, which it 

 seems closer to than to //. facta with which Binney unites it. 



As confirming the near relation of this group to Campylwa, it is notable 

 thai Mr. Binney mentions " Campyhza" lapicida (p. 379), which is so 

 similar to our angled species. If not the type of Helix, the name Ilelici- 

 gona Risso, 182G, is, however prior, if the MSS. name, Chilotrema Lead', is 



rejected. 



Mesodon Raf. 



M. townsendianus Lea. The internal characters of the animal certainly 

 connect this species more nearly with Mesodon than Arionta, and the 

 shell confirms this connection. Its more developed and reflexed lip, with 

 the lower lip furnished with a " careniform tooth" is typical, while a 

 little resemblance in sculpture is all it shows in common with Arionta. 



M. (Odotropis) dtvius Gould. In that interesting locality, Shasta, Cali- 

 fornia, Dr. Yates also found a dwarf variety of this species only about T 4 a of 

 an inch wide, and with only five whorls, evidently the Southern stunted 

 race of this Northern species, nearly like Rocky Mountain specimens. Mr. 

 Binne} 7 is certainly wrong in calling the bristly and three-toothed Triod. 

 mullani, a variety of this species, though examples with faint teeth may 

 look much like dwarfed devius. He unites them on p. 338, but on p. 432 

 shows that the jaws and teeth differ very much. On the same grounds I 

 might call the Shasta specimens loricata as they approach it in size and 

 form, or we might make half the Eastern Triodopses varieties of Mesodom. 



" Triodopsis" harfordiana Binney, not Cooper, p. 309. The shell 

 here described and figured is certainly not my shell, but seems a variety of 

 T. mullani, the differences described in jaw and Unguals not being so 

 great as in mullani and devius. My shell differs in the flat spire, unreflexed 

 lip, wider umbilicus, and 6 (not 4) whorls. In his arrangement it would 

 be a Polygyra near P. triodonloides, and is very unlikely to range in the 

 direction of Idaho. 



Mesodon (Aplodon) columbianus Lea. I am satisfied that the examina- 

 tion of a few more animals of the toothed and imperforate form found in 

 California, which so much resembles a large germanus, would prove 

 to Mr. Binney's satisfaction that there is a regular gradation in the number 

 of ribs on the jaws from 8 to 11, as stated recently by myself. Whether 

 the genitalia constantly differ as described in Oregon specimens, requires 

 further comparisons of fresh as well as alcoholic examples. 



The list on p. 18, would suggest that both these species extend to San 

 Diego, though really not found as yet south of lat. 36°, if so far. 

 Glyptostoma Binney and Bland. 



The form of jaws alone is allowed to locate this near Helix, though most 

 of its characters seem to indicate a nearer affinity to Patula. 



Patula Held.* 



Mr. Binney now unites P. cooperi with P. strigosa, but on the same 

 grounds should make all the species of the Central Province varieties of 



* The great ditfe rences in jaws of " Patula; " show that this organ must be con- 

 sidered interior to external form, &C, in classification. 



